Pulse forming networks have been extensively developed and used to supply currents having predetermined voltage and current waveforms to a load. One type of pulse forming network is similar to delay lines having series inductance and shunt capacitance, formed either by distributed or discrete components. Generally, the waveforms derived from these prior art pulse forming networks are fixed, and depend on the configuration of the delay line. In addition, for certain applications, it is desirable to use inductors as energy storage components, rather than capacitors. This is because inductors are high energy density storage devices, typically capable of storing at least 100 times more energy, in terms of volume and weight, than capacitors.
The advantages of using inductors in pulse forming networks have been previously realized, for example, in Patentschrift No. 1 488 941, Republic of Germany, filed May 31, 1966, granted Nov. 16, 1972. The pulse forming network of this reference includes a DC power supply and plural inductors, connected in series with each other and the supply. After the supply has charged the inductors with a predetermined current, the series connections between the inductors and the supply are interrupted, and the inductors are simultaneously connected in parallel to each other and the load. Thereby, the charging current initially supplied to each of the inductors is multiplied in the load, by the number of inductors. The parallel connections, in one embodiment, are established by voltage responsive switches, formed as fusable elements that are basically destroyed after each pulse is supplied by the inductors to the load. This embodiment of the device, is described as being reduced to practice in a report by W. Koch, identified as BMwF-FB K 67-35, dated Apr. 1967. This is apparently in contrast to a second embodiment of the German patent, wherein electro-mechanical switches are connected between the inductors and load during the discharge cycle. In any event, the pulse forming networks capable of delivering high current levels to a load, as disclosed in German Patentschrift No. 1 488 941, are incapable of being programmed to provide current waveforms having different shapes, controlled by the opening and closing of switches at different times during a discharge cycle.
It is, accordingly, an object of the present invention to provide a new and improved apparatus for and method of supplying a load with pulses having predetermined current waveforms in response to commands from a programmed source.
A further object of the invention is to provide a new and improved high density energy storage device capable of supplying pulses having predetermined current waveforms to a load in response to commmands derived at different times from a programmed source.
A further object of the invention is to provide a new and improved pulse forming network and method of supplying current waveforms having a predetermined shape to a load such that individual inductors and switches connected thereto need only carry a fraction of the full current supplied to a load.
An additional object of the invention is to provide a new and improved pulse forming network and method for supplying predetermined current waveforms to a load by utilizing inductive energy storage devices for supplying the load with currents in excess of the current applied by a DC power supply to any of the individual storage devices.